Pivot tables and databreaches

About a year ago I first became aware of reports of disturbing inadvertent disclosures of personal data (often highly sensitive) by public authorities who had intended only to disclose anonymous and/or aggregate data. These incidents were occurring both in the context of disclosures under the Freedom of Information Act 2000 (FOIA) and in the context of proactive disclosure of datasets. Mostly they were when what had been disclosed was not just raw data, but the spreadsheet in which the data was presented. Spreadsheet software is often very powerful, and not all users necessarily understand its capabilities (I don’t think I do). By use of pivot tables data can be sorted, summarised etc, but also, from the uninitiated or unwary, hidden. If the person who created or maintained a spreadsheet containing a pivot table is not involved in the act of publicly disclosing it it is possible that an apparently innocuous disclosure will contain hidden personal data.

Clearly such errors are likely to constitute breaches – sometimes very serious breaches – of the Data Protection Act 1998 (DPA) Those of us who were aware of a number of these inadvertent breaches were also aware that, if public authorities were not alerted to the risk a) the practice would continue and b) potentially large numbers of “disclosive” datasets would remain out in the open (in disclosure logs, on WhatDoTheyKnow, in open data sets etc). But we were also aware that, if the situation was not managed well and quietly, with authorities given the opportunity to correct/withdraw errors, inquisitive or even malicious sorts might go trawling open datasets for disclosures which could potentially be very damaging and distressing to data subjects.

It was with some relief, therefore that, following an earlier announcement by WhatDoTheyKnow, the Information Commissioner’s Office (ICO) finally gave a warning, and good guidance, on 28 June (although this relief was tempered by finding out, via Tim Turner, that the ICO had known about, and apparently done nothing about, the problem for three years). At the same time the ICO announced that it was “actively considering a number of enforcement cases on this issue”.

It appears that, according to an announcement on its own website, that Islington Council is the first recipient of this enforcement. The Council says it has

accepted a £70,000 fine from the Information Commissioner’s Office (ICO) after a mistake led to personal data being released

after it

responded to a Freedom of Information (FOI) request asking for information including the ethnicity and gender of people the council had rehoused. The response, in the form of Excel spreadsheet tables, included personal information concealed behind the summary tables

Fair play to Islington for acknowledging this and agreeing immediately to pay the monetary penalty notice. And if some of the other reported breaches I heard about were as bad as they sounded £70,000 will be at the lower end of the scale.

(thanks to @owenboswarva on twitter for flagging this up)


The ICO has now posted details of the MPN, and this clarifies that the disclosure was made on WhatDoTheyKnow and was only identifed when one of their site administrators noticed it.

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Filed under Breach Notification, Data Protection, Freedom of Information, Information Commissioner, monetary penalty notice, transparency

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